Apparatus for debarking logs

ABSTRACT

Log debarking apparatus and methods wherein a log to be debarked is presented to the nip between two rotatable log turning members and a toothed bark chipping member, the log being rotated and simultaneously moved lengthwisely in a spiral path by the turning members to enable the debarking member to remove bark from substantially the entire periphery of the log.

United States Patent 11 1 Morey et al. 1*Nov. 27, 1973 APPARATUS FOR DEBARKING LOGS [75] Inventors: Norval K. Morey, Winn; Leward N. [56] Reiereuces Cited Smith, Remus, both of Mich. NIT D STATES PATENTS 3,587,685 6/1971 Morey et a1. 144/208 F [73] Assgnee' r f Industms 3,016,074 1 1962 Baker et al. 144 208 F 3,263,720 8/1966 Brock etal 144 208 F Notice: The portion of the term of this patent subsequent to June 28, 1988, im ry Ex ner-Dona d R. SChran has been disclaimed. Attorney-Lemman & McCulloch [22] Filed: May 28, 1971 [57] ABSTRACT PP 3, 95 Log debarking apparatus and methods wherein a log Related US. Application Data Continuation-impart of Ser. No. 773,408, Nov. 5, 1968, Pat. No. 3,587,685.

to be debarked is presented to the-nip between two rotatable log turning members and a toothed bark chipping member, the log being rotated and simultaneously moved lengthwisely in a spiral path by the turning members to enable the debarking member to remove bark from substantially the entire periphery of the log.

17 Claims, 7 Drawing Figures PAIENIEU NOV 2 7 I975 sum 1 a; a

- x mm INVENTORS NORVAL K. MOREY LEWARD N. SMITH Learmcm ZVW'T ATTORNEYS Pmmmnw 1m 3.774.660

' STEIN 35F 4 FIG3 INVENTORS NORVAL K. MOREY LEWARD N. SMITH APPARATUS FOR DEBARKING LOGS THE FIELD OF THE INVENTION THE BACKGROUND OF THE INVENTION In the debarking of logs, it is quite common for successive logs to be of somewhat different diameters and, in many cases, a single log will have cross-sectional shapes which are quite irregular and of varying diameter. Such irregularities in a single log occur for various reasons, such as malformation during growth of the tree from which the log is cut and the presence of 0 knots. Irregularly shaped logs have been difficult to debark because of the inability of the log turning members used to accommodate themselves automatically to changes in log configuration. With prior art machines,

problems have been encountered because the rate of lengthwise movement imparted to the log being processed was sometimes not as suited, for bark removal purposes, to the diametral configuration or size of the log as desirable.

An object of the present invention is to provide apparatus for debarking logs wherein the speed of rotation imparted to a log by rotatable log turning members is adjusted automatically according to the diameter of the log.

A further object of the invention is to provide log debarking apparatus wherein the rate of lengthwise movement of a log through the debarking station is adjusted automatically in accordance with the shape and diameter of the portion of the log being debarked.

A further object of the invention is to provide apparatus for rotating a log while the latter is being debarked, and wherein the log rotating members accommodate themselves automatically to the contour of the log.

Early log debarking machines were provided with log turning members which were movable to accommodate logs of varying sizes, however, the inclination of the turning members relative to the log was fixed so that the feed rate of the log turning members remained constant, and the log debarking members did not efiectively remove the bark. In the referenced patent application, log debarking apparatus is disclosed which includes log turning members that adjust the spiral feed rate of the logs so that the logs of a given diameter all move axially the same distance per revolution of the logs. The axial feed rate for any given diameter log thus remains constant. If the feed rate is optimum for debarking logs of a given diameter, which are without knots, then knotty logs of this same general diameter will not be properly debarked. If the feed rate is set at a slower speed, which is optimum for knotty log portions, then the efficiency with which other log portions are debarked will decrease since they will be fed through the machine at a rate below the optimum debarking rate. Still another object of the present invention, therefore, is to provide log debarking apparatus employing log turning and feeding members which can be selectively adjusted to vary the longitudinal feed rate of a log of a given diameter.

Occasionally, it is desirable to reverse the lengthwise direction of travel of a log to debark a portion of the log surface which was not cleanly debarked due to the presence of an excessive number of knots. In such an instance, it is also desirable to maintain the same direction of log rotation. Accordingly, it is still another object of the present invention to provide log debarking apparatus including low turning members which can selectively reverse the lengthwise direction of travel of the log while maintaining the same direction of log rotation.

Known prior art debarking machines require that the logs be fed endwisely to the debarking element and thus, relatively expensive and complicated apparatus must sometimes be provided so that the logs are properly aligned with the opening between the log turning members and the debarking member. Accordingly, it is yet another object of the present invention to provide log debarking apparatus which can, if desired, be fed from in front.

With apparatus constructed according to the present invention, mechanism is provided for automatically adjusting the angles of inclination between the log turning members and the log in response to the changing diameter of the log. Also, where formerly toggle linkages were utilized to couple the turning members so that their inclinations were simultaneously adjusted when the two turning members were moved simultaneously toward and away from the log, apparatus constructed according to the present invention employs fluid responsive means for effecting such simultaneous movement.

Another object of the invention is to provide log turning and feeding mechanism having individually drivable turning means and wherein the torques or twisting forces imparted to the log by the turning means are equal regardless of the relative speeds of rotation of the several log turning members.

BRIEF SUMMARY The present invention relates to a log debarker of the type described, employing rotatable log turning members forming a log receiving nip with a chipper cylinder, and wherein the turning members are yieldably, but forcibly, maintained in log advancing engagement with the log by a fluid pressure operated cylinder, but are capable of relative movement toward and away from one another to enable logs of irregular crosssection and varying diameter to be accommodated between the turning members. With approximately cylindrical logs, the speed of rotation of each turning member is equal but the speeds are automatically varied to relate to the diameter or shape of the log at the point where the latter is engaged by the turning members to avoid slippage when logs of irregular shape are being processed. Although the speeds of the turning members will vary when a log or bolt of irregular crosssection is being debarked, both turning members are always exerting an equal torque or twisting force to rotate the log. The relative positions of the turning members and the log are adjustable so that the turning members are variably inclined to the axis of rotation of the log. The inclination of the turning members are automatically adjusted according to the diameter or shape of the log for varying the speed at which a log is moved axially through the machine.

Other objects and advantages of the invention will be pointed out specifically or will become apparent from the following description when it is considered in conjunction with the appended claims and the accompanying drawings, wherein:

FIG. 1 is a partly schematic, side elevational view of apparatus constructed according to the invention and illustrating two different positions of adjustment of the support yokes for the log turning and feeding roll members;

FIG. 2 is a fragmentary, side perspective view of the apparatus illustrated in FIG. 1, illustrating the log turning and feeding members in a different position of adjustment;

FIG. 3 is an opposite side perspective view of the apparatus illustrated in FIG. 1;

FIG. 4 is a fragmentary, enlarged, left end elevational view of the apparatus illustrated in FIG. 1;

FIG. 5 is an end elevational view of the log debarking member support table only; I

FIG. 6 is a diagrammatic view illustrating the manner in which the apparatus operates with irregularly shaped logs; and

FIG. 7 is a schematic diagram of a pressure fluid drive and control system for the machine.

Referring now more particularly to the accompanying drawings, where only a preferred embodiment of the invention is illustrated, the apparatus comprises a base frame 10 on which are mounted spaced, upstanding support column members 12 having spaced apart end plates 14 (FIG. 3) between which is mounted a rockable table 15 (FIG. 5) that supports a rotatable log debarking member, generally designated 16. The debarking member comprises a shaft 17 journaled in bearings 18 fixed to the table 15. Fixed to the shaft 17 is a cylinder or drum 19 provided with a plurality of chipping teeth 20 which engage a log L and chip the bark therefrom in a known manner. The table 15 is mounted for transverse rocking movement by means of trunnions 1 1 supported on the side members 14, the arrangement being like that disclosed in U. S. Pat. No. 3,016,074, granted Jan. 9, 1962.

The log debarking member 16 is adapted to be rotated in the direction of the arrow a (FIG. 1) by means of a sheave 22 fixed to the shaft 17 and around which may be trained belts 23 which also are trained around the output drive pulley of an internal combustion engine (not shown). A log L (see FIGS. 1 and 3) may be supported on a pair of log support shoes 24, provided at opposite ends of the drum 16 and pivotally mounted on a shaft 25 journaled by table supported bearings 26, in position to be peripherally engaged by the chipping teeth 20.

Mounted at the rear end of the frame 10 is a pair of upstanding side walls 27 spanned by cross members 28 and supporting a turning member support yoke 30 which is pivotally supported at its lower end, by means of trunnions 31 in bearings 32 provided on the frame walls 27. the yoke 30 thus is capable of rocking about a horizontal axis which is substantially parallel to the normal axis of rotation of the debarking member 16. Extending between the frame 10 and the yoke 30 is a fluid pressure operated ram 33 having its piston rod 34 pivotally connected to an arm 35 on the yoke 30. The cylinder casing 36 of ram 33 is pivotally supported by a pivot pin 37 from the machine frame 10. A source of pressure fluid (to be referred to hereinafter) constantly, but yieldably, acts on the ram 33 in such manner as to contract its length, thereby urging the yoke 30 to rock clockwisely, as viewed in FIG. 1, about the axes of trunnions 31.

At the free end of the overhanging yoke 30 is a bushing 40 in which is journaled a swivel shaft 41 (FIG. 1) which is fixed to a carrier frame 42 in which a cylindrical log turning or feeding member 45 is journaled on a shaft 46. The swivel shaft 41 turns about an axis 5 interjacent opposite ends of the feeding member 45. The periphery of the member 45 is studded with a plurality of log gripping teeth 47 (FIGS. 2 and 3) which provide a non-slip log gripping surface for the cylinder 45. The turning member 45 is mounted for counterclockwise rotation with shaft 46, in the direction indicated by arrow c (FIG. 1). The turning member support shaft 46 is driven by a rotary hydraulic motor 49 supported on the carrier 42. As illustrated in the drawings, the yoke 30 is of such length and configuration as to extend to the front side of the frame 10 and overhang a log L proceeding through the machine such that the turning member 45 frontally engages the log L.

Also supported for swinging movement on the side walls 27 is a second yoke 50 (FIG. 2) having a pair of side members 51 with integrated trunnions 52 journaled in bearings 53 fixed to the side walls 27. Rocking movement of the yoke 50 about the axes of the trunnions 52 is effected by means of a motion transmitting linkage, generally designated 54, whic interconnects the yokes 30 and 50. The linkage 54 includes a pair of plates 55 fixed to the yoke 30 and projecting from one end of the latter. To the plates 55 is pivotally connected (as at 56a) one end of a connecting rod 56, the opposite end of which is pivotally connected (as at 57a) to a pair of plates 57 fixed to the underside of the yoke 50.

Fixed to a swivel shaft a, which is journaled in the upper end of the yoke 50 is a log turning member carrier frame 58, similar to the carrier frame 42, and in which is journaled the shaft 59 to which the other log turning member or cylinder 60 is fixed, the cylinder 60 having studs or teeth 61 similar to the teeth 47. The axis 1 of the swivel shaft 60a is interjacent opposite ends of the cylinder 60. The shaft 59 is driven in the direction of the arrow c-l (FIG. 1) by means of a rotary hydraulic motor 62 which is supported by the carrier frame 58.

The construction and arrangement of the linkage 54 is such that movement of the yoke 30, either toward or away from the yoke 50, imparts corresponding movement to the latter. That is, the yokes 30 and 50 move conjointly and relatively toward and away from the log L. The relative lengths of the yokes 30 and 50, however, are such that the distance moved by the turning member 45 on yoke 30 is greater than the distance moved by the turning member 60 on yoke 50. Motors 62 and 49 may be the Char-Lynn motors manufactured by Char Lynn Company of Eden Prairie, Minn., U.S.A.

As is illustrated most clearly in FIGS. 1, 2 and 3, the axes of rotation y and z of the turning members 45 and 60 are oppositely tilted or inclined and each is inclined relatively to the axis of rotation x of the debarking member 16. In the position of the parts as illustrated in FIGS. 1 and 3, if that end of the machine adjacent the driving sprocket of the debarking member 16 is referred to as the forward or discharge end of the machine, then the axis y is inclined downwardly and forwardly relative to the axis x and inclines away from he latter in the forward direction. The axis z is inclined upwardly and forwardly relative to the axis x and inclines away from the latter in the forward direction.

The relationship among the three axes is important to the proper feeding of a log through the machine inasmuch as the inclinations of the turning members determines the rate of forward movement of the log past the debarking member 16. If a log is of relatively small diameter, it should be fed through the machine at a faster rate of speed than a log of somewhat greater diameter. The reason for this is twofold: firstly, a greater diameter log has a greater circumferential surface which must be presented to the debarking member 16 in order to remove all of the bark and, consequently, its rate of lengthwise movement must be such as to enable the entire circumference of the log to be acted upon by the debarking member. Secondly, the length of time that any given portion of a log remains in the debarking zone to subject the surface of the log to the chipping action of the teeth 20 depends on the rate at which the log is fed axially through the machine. If a portion of a log L continues to be revolved in the debarking station following the removal of its bark, then the chipping teeth will remove portions of the exposed wood surface. Apparatus constructed in accordance with the invention provides for the automatic adjustment of the inclinations of axes y and 1 relative to log L, to provide automatic adjustment of the speed of lengthwise movement of the log through the machine.

Means for adjusting the inclination of the turning member 45 comprises a coupling system, generally designated 65, having a link 66 fixed at one end to a shaft 67 joumaled for rotation in bushings 67a (FIG. 4), provided in a tubular member 68 supported by the yoke 30. The opposite end of the link 66 is pivotally connected as at 69 to a fluid pressure operated adjustment cylinder 70 (FIG. 1) having a piston rod 71 that is pivotally connected at 72 to the drum carrier 42.

As is best illustrated in FIG. 4, the shaft 67 is welded to one leg 73a of a downwardly opening U-shaped bracket 73 having a pair of legs 73a joumaling, in the lower terminal ends thereof, a shaft 76a having a follower roller 76 fixed thereto. The roller 76 is received in a cam track 77 (FIG. 1) cut in a cam plate 78 received between the legs 77a and fixed to a mounting block 79 supported from one of the side walls 27. A reinforcing tubular member 79a is concentrically disposed about the shaft 67 and is welded to the plate 66 and the U-shaped bracket 73. For a purpose to be more particularly described hereinafter, a fluid pressure operated master cylinder 74 is pivotally mounted, as at 74a, on the yoke 30 and includes a piston rod 75 pivotally connected to the carrier 42 by a pivot pin 75a.

The operation of the coupling system 65 is controlled by, movement of the yoke 30. For example, if the yoke 30 is moved counterclockwisely about the trunnions 31 from the position shown in FIG. 1, the plate 66 will tend to move counterclockwisely with the yoke. As the yoke 30 moves counterclockwisely, however, the U- shaped bracket 73, via the follower roller 75 and cam plate 78, will exert a force on the plate 66, rocking it counterclockwisely relative to the yoke 30 about the shaft 66. This movement of the plate 66 will be transmitted by the cylinder 70 and piston rod 71 to the carrier frame 42 so as to swivel the latter, together with the turning member 45, in such direction as to decrease the degree of inclination of the member 45 to the axis w of log L. That is, the axis y will be more nearly parallel to the axis w so as to change the angle of application of the thrust and decrease the lengthwise thrust imparted by the member 45 to a log. Because it is mounted on the yoke 30 for movement therewith, the follower roller 76, in a sense, feels the diameter of the log as it rides in the cam track 77. The cam track thus sets the angle of the turning member 45 relative to the log. As will later appear, it also simultaneously similarly adjusts the inclination of turning member 60. The cam track 77 can be plotted to vary the inclinations of the turning members relative to the log L, to suit a customers requirements. For example, if logs of a given diameter which are being processed are normally substantially smooth except for a small section at one end which is knotty, the cam track 77 can be designed to provide the same spiral to the log for the entire length of the log, with the exception of the small end section which is spiraled at a lower rate to insure removal of the knots as well as the bark. Depending on the plot of the track 77, therefore, the attack angle between the axes w, y and z, can be made to increase, decrease, or remain constant as the diameter of the log L increases. If, for example, the selected cam track 77 is plotted so as to decrease the angle of attack between the axes w and y, as the yoke 30 is swung counterclockwisely, the piston rod will exert a force on the piston of the cylinder 74 forcing the fluid therein to a slave cylinder, to be later described, in such a manner as to simultaneously swivel the yoke 50 so as to decrease the angle of inclination between the axes w and z a corresponding amount. As a consequence, the lengthwise thrust imposed on a log L by the turning member 60 will be reduced.

Means for adjusting the axis of the turning member 60 comprises a coupling system, generally designated C, which includes a fluid pressure operated master cylinder 74 and a fluid pressure operated slave cylinder 81, pivoted at 82 on the lower end of one of the side wall members 51, and including a piston rod 83 pivotally connected at its upper end to a plate 84 fixed to the turning member carrier frame 50. As will be described more fully in the description of the fluid circuit illustrated in FIG. 5, the operation of cylinder 81 is responsive to rocking movement of the yoke 30. The operation of the coupling systems 65 and C is such that, regardless of the positons of the turning members 45 and 60, the axes s and t of the swivel shafts 41 and 60a intersect the axes y and z, respectively and also intersect each other at a point which corresponds to the axes w of a log L interposed between the turning members 45 and 60 and the debarking member 16.

Another factor which influences the rate of rotation of a log L about its own axis, and the rate at which the log L is fed lengthwisely through the machine, is the speed at which each of the turning members 45 and 60 is rotated. To prevent slippage between the turning members and a log to be turned thereby, it is important that the peripheral speed of each turning member coincide with the peripheral speed of the log at the points where the latter is engaged by the turning members. If

a log is substantially cylindrical, the peripheral speed at each point about the circumference of the log will be substantially uniform. Under these conditions, the speeds of rotation of the two turning members 45 and 60 will correspond. It is quite unusual, however, for a log to be of uniform diameter. This is due to many reasons which are of no particular significance to the description of the present invention. It is sufficient that it be recognized that logs are normally of somewhat irregular cross-section, rather than truly cylindrical. In the debarking of an irregularly shaped log, one point on the circumference of the log may have a peripheral speed somewhat different from that of another point on the circumference of the same log. Unless the turning members are capable of adjusting their speeds to compensate for the different peripheral speeds of different circumferential portions of the log, while each is still exerting an equal torque on the log, slippage between the log and at least one of the turning members inevitably will result.

THE CONTROL CIRCUIT Apparatus constructed in accordance with the invention includes control means 85 (see FIG. 6) for controlling the speeds of rotation of the log turning members 45 and 60. The control means comprises a reservoir 86 from which hydraulic fluid may be withdrawn by a pump 87. A pressure relief valve 88 is interposed between the discharge side of the pump 87 and the reservoir 86. Fluid from the pump 87 is delivered to a four way, three position, manually operable reversing valve 89 having an operating handle 80 controllable by the machine operator. The valve 89 has a neutral position, a forward position and a reverse position. Regardless of whether the valve 89 is in its forward or reverse position, fluid is delivered to a union 91 between two identical, fixed flow, pressure compensated valves 92 and 93, each of which is adjusted so as to be capable of accommodating somewhat less than the entire discharge from the pump 87. For example, each of the valves 92 and 93 may be set to, at a maximum, accommodate approximately 75 percent of the output of the pump 87. Under normal operation the relative speeds of turning members 45 and 60 are such that one turning wheel motor would never require more than 75 percent of the pumps capacity. The flow of fluid through the valves 92 and 93 is free up to a maximum of 75 percent of the pumps flow capacity in a typical machine. Fluid passing through the valve 92 is delivered to the hydraulic motor 49, which drives the turning member 45. Fluid passing the valve 93 is delivered to the hydraulic motor 62 which drives the turning member 60. Fluid from the motors 49 and 62 is recirculated to the reservoir by means of a line 93a.

Associated with the control apparatus 85 is regulating means, generally designated 95, for controlling the relative separation or spread of the turning members 45 and 60. The regulating means comprises a pump 96 which draws fluid from the reservoir 86 and delivers it to a four-way, three-position, manually operable valve 97 which is controlled by an operating lever 98. Interposed between the pump 96 and the reservoir is a relief valve 99. Fluid from the valve 97 is delivered to a manually adjustable accumulator charge valve 100 and thence to one end of the cylinder 36 of hydraulic ram 33. The accumulator charge valve 100 also communicates with the other end of the cylinder 36, via a pneumatic accumulator 100 and a pressure gauge 102. The arrangement is such that the accumulator normally is charged so as to exert a force on the ram 33 tending to move the turning members 45 and 60 toward one another under the yieldable force of the head in the accumulator 100. When desired, however, the valve 97 may be adjusted by the machine operator so as to introduce hydraulic fluid to the cylinder 36, thereby extending the ram 33 and effecting spreading movement of the turning members 45 and 60.

Also connected to the output of the pump 96 is a four-way, three-position, manually operative valve 103 which is controlled by an operating lever 104. Fluid from the valve 103 is directed to the master cylinder 74 so as to extend the piston rod and increase the angle between the axis y of turning member 45 and axis w of log L. The cylinders 74 and 81 are connected by lines 105 and 106 so that when the piston 74a is advanced, fluid will flow through the lines 106 to the cylinder 81 to retract the piston 83 and increase the angle between the axes z and w. At the same time, fluid'is forced through the conduit 106 to the opposite end of the master cylinder 74. A line 107 is connected between line 105 and the output of accumulator 91.

The independent adjustment cylinder 70 is connected to the output of the pump 96 through a fourway, three position fluid operated valve 108 to adjust the turning members 45 and 60 with respect to axis w of the log L. It should be understood that the cylinder 70 could be replaced by a variable length arm connected between the link 66 and yoke 42.

THE OPERATION When the machine is in condition for operation, the log turning members 45 and 60 will be located adjacent one another substantially in the positions indicated in FIG. 1 as a result of the constant bias exerted on the yoke 30 by the regulating means 95. The turning members 45 and 60 will be rotating in the same rotational direction and at substantially the same speed as a result of the operation of the control means 85. The debarking member 19 will be rotating in the direction of the arrow 0 as a result of the operation of its driving motor. Under these conditions, a log L may be introduced to the machine, whereupon it will enter the nip between the three rotating members 19, 45 and 60. The table 15 will rock about its trunnions 11 to assist entry of the log. As the log is introduced between the rotating members, the engagement of the log with the members 45 and 60 will cause the latter to be spread apart slightly as is permitted by the accumulator 100. The application of force by the log on the turning member 45, tending to move it away from the debarking member 19, will cause the yoke 30 to rock counterclockwisely, as viewed in FIG. 1, and such movement of the yoke 30 automatically will be transmitted via the linkage 54 to the yoke 50 to cause the latter to swing clockwisely. The turning members 45 and 60 thus will be moved apart a distance to accommodate the log L therebetween, but the pneumatic head in the accumulator 101 constantly will exert a force on the ram 33 tending to move the turning members 45 and 60 toward one another, thereby maintaining the turning members in engagement with the log L, and the latter in engagement with the debarking member 19.

The speeds of rotation of the turning members 45 and 60 are determined by the fluid flow through the respective valves 92 and 93. Thus, if a greater quantity of fluid flows through one of the valves, the turning member associated with it will rotate at a faster speed than the other turning member.

The speed at which each turning member rotates is directly proportional to the length of the radial from the axis of rotation of the log to each respective turning member. In the case of the log L, shown in FIG. 1, the radial distance from the axis w to each of the turning members is substantially the same, so the speeds of rotation of the two turning members should substantially coincide. In the case of the log L, illustrated in FIG. 6, however, this is not true. In FIG. 6, the radial distance D from the axis r of the log L to the periphery of the turning member 60 is less than the radial distance D+ from the axis r to the periphery of the turning member 45.

In the positions of the turning members illustrated in FIG. 6, the linear speed of the peripheral portion of the log L adjacent the turning member 45 is somewhat greater than the linear speed of the peripheral portion of the log adjacent the periphery of the turning member 60. If there is to be no slippage of either turning member relative to the log L, therefore, the speed of rotation of the turning member 45 must be greater than that of the turning member 60. The flow of hydraulic fluid necessary to drive the member 60 at a speed less than that of the turning member 45 is less than the flow of fluid necessary to drive the turning member 45 at the higher speed. The two valves 92 and 93, by reacting to any tendency of one turning member to slip or free wheel, automatically will adjust the flow of hydraulic fluid through the respective motors 49 and 62. When the log L has been rotated 180 from the position illustrated in FIG. 6, the axis r of rotation of the log L will shift. In this instance, it will be necessary for the speed of rotation of the turning member 60 to exceed that of the turning member 45.

The application of equal torques or twisting forces by both turning members 45 and 60 is assured by the setting of the valves 92 and 93 in such manner that neither can accommodate the full output of fluid from the pump 87. Thus, even though the flow of fluid through the valves 92 and 93 will follow the course of least resistance and be diverted to the turning member offering the least resistance to rotation, some of the driving fluid will be diverted to the other turning member, thereby preventing any possibility of freewheeling of one tuming member such that no driving force is being exerted by it on the log. Such slippage causes horsepower and drive problems which do not occur where each turning member in effect chooses its own speed. The speed of rotation of the log turning members 45 and 60 is governed by the flow of fluid, whereas the driving torque delivered by each is governed by the pressure of the fluid, which is always the same for each motor. Thus, the output torque of each turning member is always the same since they transmit the same force through the same radial distance. The turning force or output torque thus exerted on the log by each turning member is always equal to the turning force or output torque exerted on the log by the other turning member.

Although the speeds of rotation of the turning members 45 and 60 may vary, each will exert its proportionate share of force on a log to feed the latter lengthwisely through the machine. The lengthwise driving force exerted on the logs by the respective turning member is a function of the degree of inclination of the axes y and z to the axis w of the log and to the ability of the turning members to exert equal torque on a log therebetween. The capacity of the pump 87 should be so selected that when the turning members 45 and 60 are in their positions of closest proximity, the relative inclination of the axes y and z and the relative speeds of rotation of the turning members are such that the log will be fed spirally through the machine at a rate of speed such that the chipping teeth 20 will effect complete debarking of the log.

The rate of lengthwise movement of a small diameter log obviously can be greater than that of a large diameter log inasmuch as the smaller diameter log has less circumference to be debarked. The operation of the system is such that, the greater the distance apart the turning members 45 and 60 are moved to accommodate the log therebetween, the lesser is the inclination of the axes y and z. Consequently, the forward lengthwise speed of movement of a larger diameter log through the machine is less than that of a smaller diameter log.

As illustrated in solid lines in FIG. 5, a knot K on a log L" may engage the right log supporting shoe 24. If the log turning members 45 and 60 are positioned as illustrated in FIG. 2, and the log is moving lengthwisely forwardly in the direction of the arrow d at a speed such that the knot K, after completing one revolution, engages the left hand shoe 24, as shown at K, and never contacts or is removed by the chipping teeth, then the portions 81a and 82a of the log immediately adjacent knot K will not be debarked.

With apparatus constructed according to the present invention, there is a way of recitifying this situation. By manipulating valve 89, the log turning members 45 and 60 may be swung sufficiently about the axes of the swivel shafts 41 and 60a respectively to move the log lengthwisely in a reverse direction so that the knot K will be returned past the debarking member 19 at a feed rate to contact the knot with the chipping teeth 20 and remove it, and also remove the bark at log portions 81 and 82. The log turning members are then returned to original positions to forward the log L" in the direction of the arrow d. It should be noted that, although the turning members are disposed with an opposite tilt during the reversing operation, they are still revolving in the same direction so that the log L" continues to revolve in the same direction even though it is lengthwisely moved in the opposite direction. This is important to maintain the relative turning speeds of the log turning members and the log debarking member 19.

The capability of selectively manually varying the spiral of the log via valves 89 or 108 enables an operator to feed a log of any given diameter (within the dimensions of the machine) at a changed lengthwise velocity. If, as frequently occurs, the ends of the logs being fed are heavily knotted, the lengthwise feed can be slowed substantially to insure that all knots are removed and the log is fully debarked.

In the operation of the apparatus, any log that is too large in diameter to enter the nip between the members 45, 60 and 19, when the latter are in their relatively closed positions, may be admitted to the machine upon the operators manipulating the valve 97 so as to enable fluid from the pump 96 to extend the ram 33 and force the turning members and 60 away from one another. Thereafter, when the operator releases the valve operating handle, the accumulator 101 acts on the ram 33 to urge the members 45 and 60 toward one another so as to maintain both turning members in driving engagement with the log.

Logs presented to the debarking machine conventionally follow one another in end-to-end relation. Consequently, any succeeding log that is the same or smaller in diameter than the immediately preceding log may be introduced between the turning members 45 and 60 without operator attention to the valve 97.

The disclosed apparatus is representative of a presently preferred embodiment of the invention, but is intended to be illustrative rather than definitive thereof. The invention is defined in the claims.

I claim:

1. Log debarking apparatus comprising:

a debarking member rotatable about an axis and having bark removing members thereon;

a pair of log turning members having log gripping torque transmitting parts thereon, each member being rotatable about its own longitudinal axis and swingable about a transverse axis interjacent its ends, each of said turning members being movable to various positions of inclination relative to said debarking member;

means for rotating said log turning members in the same direction of rotation and normally at the same speed of rotation to spiral the log axially past said debarking member;

means rotating said debarking member in a direction to oppose the rotation of the log imparted by said turning members and at a speed to cut bark from substantially the entire periphery of the log;

means mounting said turning members for movement toward and away from said debarking member dependent upon the diameter of the log to maintain the log turning members in gripping relation with the log; and

means automatically responsive to movement of said turning members toward and away from said debarking member for swinging the turning members about said transverse axes to vary the inclination of said turning members in a manner such that, regardless of the positions of the turning members, each log turning member is inclined to the log to direct the log axially at the same forwarding speed and in the same direction as the other log turning member.

2. The apparatus set forth in claim 1 wherein the transverse axes about which the turning members are swingable and the turning axes of the respective turning members intersect, said transverse axes always intersecting at a point substantially corresponding to the axis of rotation of a log gripped between two turning members.

3. The apparatus set forth in claim 1 wherein said swinging means is operative to swing said turning members between positions in which a log gripped by said turning members is forwarded lengthwisely in a first direction and positions in which a log gripped by said turning members is forwarded lengthwisely in an opposite direction while the direction of rotation of the log remains the same.

4. Log debarking apparatus comprising a debarking member rotatable about an axis and having bark removing members thereon;

a pair of log turning members having log gripping, torque transmitting parts thereon, each lOg turning member being rotatable about its own axis and being swingable about a transverse axis which is interjacent the ends of the log turning member and which intersects the rotational axis of the log turning member, said log turning members being inclined relatively to the axis of said debarking member; means for rotating said log turning members in the same direction of rotation and normally at the same speed of rotation to spiral the log about its own axis axially past said debarking member; means rotating said debarking member in a direction to oppose the rotation of the log imparted by said turning members and at a speed to cut bark from substantially the entire periphery of the log; means mounting said turning members for movement toward and away from said debarking member dependent upon the diameter of the log to maintain the log turning members in gripping relation with the log; and means automatically responsive to movement of said turning members toward and away from said debarking member for swinging the turning members about said transverse axes to vary the inclination of said rotational axes in a manner such that regardless of the positions of the turning members, said transverse axes will always intersect at a point substantially corresponding to the axis of rotation of a log gripped between the two turning members.

5. Log debarking apparatus comprising: a debarking member rotatable about an axis and having bark removing members thereon;

a frame;

a pair of rotatable log turning members, having log gripping torque transmitting parts thereon, rotatable about their respective rotational axes and being swivelably mounted on said frame for movement about swivel axes to relatively inclined positions in which the rotational axes of said turning members are inclined relatively to the axis of said debarking member;

means for rotating said log turning members in the same direction of rotation and normally at the same speed of rotation, to rotate the log about its axis and move it axially past said debarking member;

means rotating said debarking member in a direction to oppose the rotation of the log imparted by said turning members and at a speed to cut bark from substantially the entire periphery of the log;

means mounting said turning members on said frame for movement toward and away from said debarking members dependent upon the diameter of the log to maintain the turning members in gripping relation with the log; and

means, including fluid pressure operative apparatus,

automatically responsive to movement of said turning members toward and away from said debarking member for swiveling said turning members about said swivel axes to vary the inclination of said turning member axes relative to the axis of the log to control the rate of axial movement of the log.

6. The apparatus set forth in claim 5 wherein said fluid pressure operative apparatus comprises fluid pressure operated master cylinder means mechanically coupled to one of said turning members and fluid pressure operated slave cylinder means mechanically coupled to the other of said turning members, the master and slave cylinder means being in fluid communication with each other such that when said one turning member moves toward and away from said debarking member, fluid is caused to flow between said master and slave cylinder means to move the other of said turning members toward and away from, respectively, said debarking member.

7. The apparatus of claim wherein said mount means for said turning members supports said fluid pressure operative means; said means for swiveling said turning members comprises means carried by said mount means for controlling the operation of said fluid pressure operative means.

8. The apparatus of claim 5 wherein said swiveling means includes cooperative camming means and cam follower means on said frame and one of said turning members for swiveling said one turning member about its swivel axes; said fluid pressure responsive means being responsive to the swiveling of said one turning member to swivel the other turning member about its swivel axis to vary the inclination of said turning member axes.

9. The apparatus set forth in claim 5 including adjustable means for adjusting the position of one of said turning members about its swivel axis toward and away from said log debarking member to vary the relative inclination of said one turning member and a log of a given diameter;

said fluid pressure operative means including means responsive to said swiveling of said one turning member to similarly turn the other turning member.

10. The apparatus set forth in claim 5 wherein said mounting means comprises pivotal means swingably mounted on said frame and supporting one of said tuming members; said responsive means including means movable with and relative to said pivotal means for swiveling said one turning means a distance dependent upon the diameter of the log being debarked.

11. The apparatus set forth in claim wherein said pivotal means comprises linkage means connected between said tuming members for simultaneously moving the other of said turning means toward and away from the log being debarked when said one of said members moves toward the log being debarked.

12. The apparatus set forth in claim 10 including adjustable link means reactable between said pivotal means and said one turning member to selectively swivel said one turning means independent of the diameter of the log being debarked.

13. The log debarking apparatus as set forth in claim 5 wherein one of said turning means is disposed on the rearward side of the axis of said debarking member and the other of said turning means is supported on the front side of the axis of said debarking member for swinging movement about an axis on said one side of said debarking member so that a log may be front fed to the nip formed between said turning members and said debarking member.

14. Log debarking apparatus which can be front fed comprising: a frame; a debarking member mounted on said frame for rotation about an axis; a pair of rotatable log turning members mounted on said frame for movement toward and away from said debarking member and forming a nip for gripping a log therebetween; means for rotating said log turning members in the same direction of rotation to spiral the log axially past the debarking member in the opposite direction of rotation; one of said log turning members being disposed generally rearwardly of the log debarking member and supported on the frame for swinging movement about an axis which is rearward of the axis of said debarking member, the other of said log turning members being disposed generally forwardly of said turning member and being swingable about an axis at the rear side of the debarking member to permit a log to be fed to the debarking member from the front of the apparatus.

15. Log debarking apparatus comprising:

a frame;

a debarking member mounted on said frame for rotation about an axis and having bark removing members thereon;

a pair of log turning members, having log gripping torque transmitting parts thereon, rotatable about their respective axes and being swivelably movable about swivel axes to inclined positions in which the turning members are inclined relatively to the axis of said debarking member;

means for rotating said log turning members in the same direction of rotation and normally at the same speed of rotation, to rotate the log about its axis and move it axially past said debarking member;

means rotating said debarking member in a direction to oppose the rotation of the log imparted by said turning members and at a speed to cut bark from substantially the entire periphery of the log;

means mounting said turning members on said frame for movement toward and away from said debark ing member dependent upon the diameter of the log to maintain the turning members in gripping relation with a log being debarked;

means automatically responsive to movement of said turning members toward and away from said debarking member for swiveling said turning members about said swivel axes to vary the inclination of said turning member relative to the axis of the log and control the rate of axial movement of the log; and

manually operable means for overriding said swiveling means to independently swivel said turning member about said swivel axes to vary the inclination of said turning members relative to the axis of the log being debarked.

16. Log debarking apparatus comprising:

a frame;

a debarking member mounted on said frame for rotation about an axis and having bark removing members thereon;

a pair of log turning members, having log gripping torque transmitting pans thereon, being rotatable about their respective axes and being swivelably movable about swivel axes to relatively inclined positions in which the turning members are inclined relatively to the axis of said debarking member;

means for rotating said log turning members in the same direction of rotation and normally at the same speed of rotation, to rotate the log about its axis and move it axially past said debarking member;

means rotating said debarking member in a direction to oppose the rotation of the log imparted by said turning members and at a speed to cut bark from substantially the entire periphery of the log;

means mounting said turning members on said frame for movement toward and away from said debarking member dependent upon the diameter of the log to maintain the log turning members in gripping relation with a log being debarked;

and cam means automatically responsive to movement of said turning members toward and away from said debarking member for swiveling said turning members about said swivel axes to vary the inclination of said turning member axes relative to the axis of the log to control the rate of axial movement of the log 17. Log debarking apparatus comprising:

a frame;

a debarking member, having bark removing members thereon, mounted on said frame for movement in a debarking path of travel; and

means for rotating a log about its axis while feeding it past said debarking member including:

a pair of log feeding roll members having log gripping, torque transmitting parts thereon, each log feeding member being rotatable about its own longitudinal axis and swingable about a transverse axis interjacent its ends, each of said log feeding members being movable to various positions of inclination relative to said debarking member;

means for rotating said log feeding members to spiral a gripped log axially past said debarking member;

means for driving said debarking member at a speed to cut bark from substantially the entire circumference of a log moved thereby by said log feeding members;

means mounting said log feeding members for movement toward and away from said debarking member dependent upon the diameter of the log to maintain the log feeding members in gripping relation with the log;

means responsive to movement of said log feeding members toward and away from said debarking member for swinging the log feeding members about said transverse axes to vary the inclination of said log feeding members and control the rate of axial movement of the log; and

means for individually adjusting the rotational speed of each of said log feeding members individually in response to the distance of the feeding member from the rotary axis of the log. 8K 

1. Log debarking apparatus comprising: a debarking member rotatable about an axis and having bark removing members thereon; a pair of log turning members having log gripping torque transmitting parts thereon, each member being rotatable about its own longitudinal axis and swingable about a transverse axis interjacent its ends, each of said turning members being movable to various positions of inclination relative to said debarking member; means for rotating said log turning members in the same direction of rotation and normally at the same speed of rotation to spiral the log axially past said debarking member; means rotating said debarking member in a direction to oppose the rotation of the log imparted by said turning members and at a speed to cut bark from substantially the entire periphery of the log; means mounting said turning members for movement toward and away from said debarking member dependent upon the diameter of the log to maintain the log turning members in gripping relation with the log; and means automatically responsive to movement of said turning members toward and away from said debarking member for swinging the turning members about said transverse axes to vary the inclination of said turning members in a manner such that, regardless of the positions of the turning members, each log turning member is inclined to the log to direct the log axially at the same forwarding speed and in the same direction as the other log turning member.
 2. The apparatus set forth in claim 1 wherein the transverse axes about which the turning members are swingable and the turning axes of the respective turning members intersect, said transverse axes always intersecting at a point substantially corresponding to the axis of rotation of a log gripped between two turning members.
 3. The apparatus set forth in claim 1 wherein said swinging means is operative to swing said turning members between positions in which a log gripped by said turning members is forwarded lengthwisely in a first direction and positions in which a log gripped by said turning members is forwarded lengthwisely in an opposite direction while the direction of rotation of the log remains the same.
 4. Log debarking apparatus comprising a debarking member rotatable about an axis and having bark removing members thereon; a pair of log turning members having log gripping, torque transmitting parts thereon, each log turning member being rotatable about its own axis and being swingable about a transverse axis which is interjacent the ends of the log turning member and which intersects the rotational axis of the log turning member, said log turning members being inclined relatively to the axis of said debarking member; means for rotating said log turning members in the same direction of rotation and normally at the same speed of rotation to spiral the log about its own axis axially past said debarking member; means rotating said debarking member in a direction to oppose the rotation of the log imparted by said turning members and at a speed to cut bark from substantially the entire periphery of the log; means mounting said turning members for movement toward and away from said debarking member dependent upon the diameter of the log to maintain the log turning members in gripping relation with the log; and means automatically responsive to movement of said turning members toward and away from said debarking membEr for swinging the turning members about said transverse axes to vary the inclination of said rotational axes in a manner such that regardless of the positions of the turning members, said transverse axes will always intersect at a point substantially corresponding to the axis of rotation of a log gripped between the two turning members.
 5. Log debarking apparatus comprising: a debarking member rotatable about an axis and having bark removing members thereon; a frame; a pair of rotatable log turning members, having log gripping torque transmitting parts thereon, rotatable about their respective rotational axes and being swivelably mounted on said frame for movement about swivel axes to relatively inclined positions in which the rotational axes of said turning members are inclined relatively to the axis of said debarking member; means for rotating said log turning members in the same direction of rotation and normally at the same speed of rotation, to rotate the log about its axis and move it axially past said debarking member; means rotating said debarking member in a direction to oppose the rotation of the log imparted by said turning members and at a speed to cut bark from substantially the entire periphery of the log; means mounting said turning members on said frame for movement toward and away from said debarking members dependent upon the diameter of the log to maintain the turning members in gripping relation with the log; and means, including fluid pressure operative apparatus, automatically responsive to movement of said turning members toward and away from said debarking member for swiveling said turning members about said swivel axes to vary the inclination of said turning member axes relative to the axis of the log to control the rate of axial movement of the log.
 6. The apparatus set forth in claim 5 wherein said fluid pressure operative apparatus comprises fluid pressure operated master cylinder means mechanically coupled to one of said turning members and fluid pressure operated slave cylinder means mechanically coupled to the other of said turning members, the master and slave cylinder means being in fluid communication with each other such that when said one turning member moves toward and away from said debarking member, fluid is caused to flow between said master and slave cylinder means to move the other of said turning members toward and away from, respectively, said debarking member.
 7. The apparatus of claim 5 wherein said mount means for said turning members supports said fluid pressure operative means; said means for swiveling said turning members comprises means carried by said mount means for controlling the operation of said fluid pressure operative means.
 8. The apparatus of claim 5 wherein said swiveling means includes cooperative camming means and cam follower means on said frame and one of said turning members for swiveling said one turning member about its swivel axes; said fluid pressure responsive means being responsive to the swiveling of said one turning member to swivel the other turning member about its swivel axis to vary the inclination of said turning member axes.
 9. The apparatus set forth in claim 5 including adjustable means for adjusting the position of one of said turning members about its swivel axis toward and away from said log debarking member to vary the relative inclination of said one turning member and a log of a given diameter; said fluid pressure operative means including means responsive to said swiveling of said one turning member to similarly turn the other turning member.
 10. The apparatus set forth in claim 5 wherein said mounting means comprises pivotal means swingably mounted on said frame and supporting one of said turning members; said responsive means including means movable with and relative to said pivotal means for swiveling said one turning means a distance dependent upon the diameter of the log being debarked.
 11. The apparatus set forth in Claim 10 wherein said pivotal means comprises linkage means connected between said turning members for simultaneously moving the other of said turning means toward and away from the log being debarked when said one of said members moves toward the log being debarked.
 12. The apparatus set forth in claim 10 including adjustable link means reactable between said pivotal means and said one turning member to selectively swivel said one turning means independent of the diameter of the log being debarked.
 13. The log debarking apparatus as set forth in claim 5 wherein one of said turning means is disposed on the rearward side of the axis of said debarking member and the other of said turning means is supported on the front side of the axis of said debarking member for swinging movement about an axis on said one side of said debarking member so that a log may be front fed to the nip formed between said turning members and said debarking member.
 14. Log debarking apparatus which can be front fed comprising: a frame; a debarking member mounted on said frame for rotation about an axis; a pair of rotatable log turning members mounted on said frame for movement toward and away from said debarking member and forming a nip for gripping a log therebetween; means for rotating said log turning members in the same direction of rotation to spiral the log axially past the debarking member in the opposite direction of rotation; one of said log turning members being disposed generally rearwardly of the log debarking member and supported on the frame for swinging movement about an axis which is rearward of the axis of said debarking member, the other of said log turning members being disposed generally forwardly of said turning member and being swingable about an axis at the rear side of the debarking member to permit a log to be fed to the debarking member from the front of the apparatus.
 15. Log debarking apparatus comprising: a frame; a debarking member mounted on said frame for rotation about an axis and having bark removing members thereon; a pair of log turning members, having log gripping torque transmitting parts thereon, rotatable about their respective axes and being swivelably movable about swivel axes to inclined positions in which the turning members are inclined relatively to the axis of said debarking member; means for rotating said log turning members in the same direction of rotation and normally at the same speed of rotation, to rotate the log about its axis and move it axially past said debarking member; means rotating said debarking member in a direction to oppose the rotation of the log imparted by said turning members and at a speed to cut bark from substantially the entire periphery of the log; means mounting said turning members on said frame for movement toward and away from said debarking member dependent upon the diameter of the log to maintain the turning members in gripping relation with a log being debarked; means automatically responsive to movement of said turning members toward and away from said debarking member for swiveling said turning members about said swivel axes to vary the inclination of said turning member relative to the axis of the log and control the rate of axial movement of the log; and manually operable means for overriding said swiveling means to independently swivel said turning member about said swivel axes to vary the inclination of said turning members relative to the axis of the log being debarked.
 16. Log debarking apparatus comprising: a frame; a debarking member mounted on said frame for rotation about an axis and having bark removing members thereon; a pair of log turning members, having log gripping torque transmitting parts thereon, being rotatable about their respective axes and being swivelably movable about swivel axes to relatively inclined positions in which the turning members are inclined relatively to the axis of said debarking member; means for rotAting said log turning members in the same direction of rotation and normally at the same speed of rotation, to rotate the log about its axis and move it axially past said debarking member; means rotating said debarking member in a direction to oppose the rotation of the log imparted by said turning members and at a speed to cut bark from substantially the entire periphery of the log; means mounting said turning members on said frame for movement toward and away from said debarking member dependent upon the diameter of the log to maintain the log turning members in gripping relation with a log being debarked; and cam means automatically responsive to movement of said turning members toward and away from said debarking member for swiveling said turning members about said swivel axes to vary the inclination of said turning member axes relative to the axis of the log to control the rate of axial movement of the log.
 17. Log debarking apparatus comprising: a frame; a debarking member, having bark removing members thereon, mounted on said frame for movement in a debarking path of travel; and means for rotating a log about its axis while feeding it past said debarking member including: a pair of log feeding roll members having log gripping, torque transmitting parts thereon, each log feeding member being rotatable about its own longitudinal axis and swingable about a transverse axis interjacent its ends, each of said log feeding members being movable to various positions of inclination relative to said debarking member; means for rotating said log feeding members to spiral a gripped log axially past said debarking member; means for driving said debarking member at a speed to cut bark from substantially the entire circumference of a log moved thereby by said log feeding members; means mounting said log feeding members for movement toward and away from said debarking member dependent upon the diameter of the log to maintain the log feeding members in gripping relation with the log; means responsive to movement of said log feeding members toward and away from said debarking member for swinging the log feeding members about said transverse axes to vary the inclination of said log feeding members and control the rate of axial movement of the log; and means for individually adjusting the rotational speed of each of said log feeding members individually in response to the distance of the feeding member from the rotary axis of the log. 